A single-photon detector provides the ultimate limit of extremely weak electromagnetic radiation detection in term of sensitivity. Compact solid-state single-photon detectors are regarded as enabling components in a wide range of applications such as biophotonics, tomography, homeland security, non-destructive material inspection, astronomy, quantum key distribution, and quantum imaging. Despite the astonishing progress of these fields in recent years, there has been little progress in the performance of single-photon detectors, and thus the single-photon detector is quickly becoming the “bottleneck” in these fields. Some of the important shortcomings of the current single-photon detectors are: poor quantum efficiency, high dark count rates, lack of imaging arrays, severe cooling requirement for longer wavelengths, and large dead-times (low bandwidth) due to after-pulsing. Unfortunately, these problems become much more significant for wavelengths beyond the visible range where a large number of applications can benefit the most. In particular, these drawbacks have prevented demonstration of the much-needed high-performance single-photon detectors beyond the visible wavelength, and high-performance arrays of single-photon detectors.